Abstract Background Rapid molecular diagnostics such as the BioFire FilmArray Pneumonia Panel (the Pneumonia Panel) can improve antibiotic stewardship by supporting doctors to make more targeted antibiotic prescribing decisions faster compared to routine microbiology. However, factors influencing how these test results translate to individual prescribing decisions are poorly understood. The INHALE randomised controlled trial (RCT) evaluated the application of the Pneumonia Panel to manage suspected hospital-acquired and ventilator-associated pneumonias (HAP/VAP) in English intensive care unit (ICU) patients. This behavioural study examines clinicians perceived and actual antibiotic prescribing behaviour, within the INHALE RCT. Methods Clinicians treating ICU patients completed brief questionnaires within 24 h of their prescribing decision for intervention-arm cases (N = 159), exploring factors influencing their decision and perceptions about the test results. Actual prescribing behaviour was extracted from the trial database. A 4-block hierarchical logistic regression identified predictors of prescriptions being consistent with Pneumonia Panel results. Results 65% (N = 104) of prescribing decisions were consistent with Pneumonia Panel results. The test result itself was a dominant factor: 88% (N = 98) of decisions were consistent when results were positive (pathogens found). However, only 13% (N = 6) of decisions were consistent when no pathogens were detected. Consequently, clinicians were often reluctant to eschew initial antibiotics or de-escalate early where appropriate, ‘erring on the side of caution’. Clinicians perceptions, specifically the speed of results, concurrent antibiotic treatment, the patient having additional confirmed evidence of infection, and believing the patient is unlikely to have a non-respiratory infection predicted prescribing decisions being aligned with test results (all p < .05). Conclusions Findings have implications for the roll-out of rapid diagnostics in practice, particularly regarding the management of negative results. Implementation strategies need to be behaviourally intelligent, connecting with how clinicians think and behave.

BACKGROUND:Hospital ward strain occurs when care demands exceed available staffing, beds, and resources, posing a significant threat to safe inpatient care. While emergency department and intensive care settings have been extensively studied, ward-level pressures have received less attention, particularly from the perspectives of patients and frontline staff. This review aimed to synthesize current evidence on how hospital ward strain is experienced by staff and patients, and its implications for care quality, safety, and workforce sustainability. METHODS:A mixed methods systematic review was conducted on patient and staff perspectives on hospital ward strain. MEDLINE, CINAHL, PsycINFO, and HMIC were searched for empirical studies published from January 2000 to March 2025. Three reviewers screened titles and abstracts in pairs; full-text assessment was conducted by one reviewer with independent verification of a random 20% sample. The Mixed-Methods Appraisal Tool was used to assess methodological quality. Findings were analysed using Donabedian's Structure-Process-Outcome (SPO) model and Hollnagel's Resilience framework. RESULTS:Of 9,943 studies identified, 16 observational and non-randomized studies met the inclusion criteria, representing diverse healthcare settings across multiple countries. Most studies (87.5%) focused exclusively on staff perspectives; only two included patient experiences. Structural pressures (inadequate staffing, bed capacity constraints) consistently led to process failures (care delays, missed care, coordination breakdowns), resulting in burnout, turnover, quality and safety trade-offs, and compromised patient safety. Ward resilience was mainly reactive: respond and monitor were evident, but anticipate and learn, were mostly absent. Patient acuity was inconsistently reported, limiting cross-study comparison. CONCLUSION:Ward strain is a systemic patient safety issue requiring structural solutions beyond staff resilience. Patient perspectives remain underrepresented and must be prioritized in future research. Policymakers should invest in anticipatory and learning resilience capacities through workforce planning, real-time monitoring, and formal learning mechanisms, to ensure sustainable, safe ward care.

Abstract Background Reliably distinguishing infection from sterile inflammation is a major clinical challenge. Uncertainty can lead to unnecessary courses of antibiotics, fueling antimicrobial resistance and adverse effects. Calprotectin, a biomarker released by activated immune cells, may inform decision-making. Methods This prospective, observational, single-centre study recruited patients with suspected infection who provided blood samples on enrolment from the Emergency Department (ED) and Intensive Care Unit (ICU) of a central London university hospital. A separate longitudinal study with five days’ blood sampling was performed in patients undergoing elective major non-cardiac surgery, in whom infection was adjudicated according to the Standardised Endpoints in Perioperative Medicine (StEP) initiative. Diagnostic adjudication was performed blinded to calprotectin. The primary outcome was the ability of calprotectin to diagnose infection. Secondary outcomes included a comparison to C-reactive protein (CRP). Results 427 patients were included, of whom 186 (44%) were female. Of 245 ED patients, 71 (29%) had active cancer and 56 (23%) were on immunosuppressants. The median calprotectin level in the no-infection group was 1.97 mg/L (IQR 1.02–3.39), compared to 2.76 (IQR 1.65–5.08) mg/L in low-probability infection, 2.63 mg/L (IQR 1.83–5.23) in high-probability infection, and 2.64 mg/L (IQR 1.49–4.45) in patients with confirmed infection. Ordinal regression analysis found no meaningful association between calprotectin levels and infection, or bacterial infection. Logistic regression showed an unadjusted AUC of 0.53 (95%-CI 0.45–0.62) for calprotectin and a binary outcome of infection compared to an AUC of 0.63 (95%-CI 0.55–0.71) for CRP. Similar results were seen in a sensitivity analysis excluding patients with cancer or immunosuppression. In 98 ICU patients, neither calprotectin nor CRP showed a meaningful association with an adjudicated diagnosis of infection or ICU death. In the peri-operative cohort, calprotectin levels remained elevated over 5 days, but with no difference between patients developing or not developing infection. Conclusion Calprotectin showed only limited ability to differentiate infection from inflammation across ED, ICU, and elective surgery patients. Excluding patients with cancer or immunosuppression did not alter the overall findings.

Sepsis is associated with immunosuppression, predisposing patients to secondary infections. Many treatments routinely used for infections have immunomodulatory effects, including antibiotics. We therefore assessed the immunomodulatory effects of beta-lactam antibiotics on monocyte and lymphocyte immunophenotype. Peripheral blood mononuclear cells isolated from Emergency Department patients with bacterial infection were incubated with narrow-spectrum (amoxicillin and cefuroxime) or broad-spectrum (piperacillin-Tazobactam and meropenem) beta-lactam antibiotics at low and high concentrations. We compared the effects of antibiotics with and without an additional stimulus, LPS for 24 h or anti-CD3/CD28 beads for 72 h to evaluate the effect on monocyte and lymphocyte phenotype respectively. Using spectral flow cytometry, we evaluated functional markers associated with immune activation and reproducible phenotypes consistent with sepsis-induced immunosuppression. Beta-lactams, at higher-dose, were associated with increased monocyte CCR2 and decreased CD14 expression. Cefuroxime, meropenem and piperacillin had additional effects, causing a reduced monocyte HLA-DR, NOX-2, CLIP, and NF-κB expression with increased CD80. Beta-lactam exposure was associated with increased CD4+ lymphocyte viability, whilst amoxicillin had additional effects including reduced PD-1 expression and proliferation, and increased IL-7R expression. Changes to immune cell phenotype were minimal in CD8+ lymphocytes, at lower antibiotic doses, or in unstimulated cells. Beta-lactam antibiotics have immunomodulatory effects in vitro, including changes consistent with sepsis-induced immunosuppression at clinically relevant doses. Further work is required to determine the mechanisms underpinning these observations and clinical implications, which may have significant clinical implications on the type and duration of antibiotics administered, and highlight the need for therapeutic antibiotic monitoring.

COV-SARS-2 targets alveolar type II cells. As these cells synthesise lung surfactant, we hypothesised that surfactant dysfunction may contribute to development of ARDS in COVID-19. Here we report turnover of surfactant delivered to patients ventilated for severe COVID-19 using a novel breath-synchronized nebulizer compared with a control group. Endogenous surfactant status, turnover and half-life of administered surfactant and tracheal aspirate (TA) phospholipid metabolism were analysed by lipidomic mass spectrometry. At enrolment shortly after intubation, TA analysis (n = 20) showed markedly reduced concentrations of surfactant phospholipids, consistent with surfactant depletion. In a dose-range study in 12 ventilated COVID-19 patients with ARDS, administered surfactant resulted mean 20-fold (range 6.4 and 60.3) excess over endogenous lipid, providing proof of concept for effective nebulization, with a very rapid turnover (median half-life 7.8, range 0.4 to 20.8 h). Neither the rate of endogenous TA phosphatidylcholine (PC) synthesis nor the composition of newly synthesised PC, determined by incorporation of methyl-D9-choline, were significantly altered by exogenous surfactant nebulization. An inverse correlation between the fractional synthesis of dipalmitoyl phosphatidylcholine and inflammatory status suggested that a significant portion of endogenous TA phospholipid was derived from non-surfactant sources. This analysis is the first direct demonstration of surfactant deficiency in COVID-19; while exogenous surfactant can correct this deficiency, its rapid turnover suggests that prolonged treatment with surfactant will be needed.

BACKGROUND:Acute respiratory distress syndrome (ARDS) is a clinically defined, biologically heterogeneous condition with no proven disease-modifying therapies. Retrospective analyses have identified two biologically distinct subphenotypes (hyperinflammatory and hypoinflammatory) of ARDS, with differing outcomes and responses to therapy. Rapid identification of these subphenotypes in an actionable timeframe has previously not been possible. The PHIND study aimed to prospectively identify these subphenotypes and to demonstrate differing 60-day mortality. METHODS:The PHIND study was a prospective, multicentre, observational cohort study conducted in intensive care units (ICUs) within the National Health Service in the UK and the Health Service Executive in Ireland. Adult patients aged 18 years and older with ARDS or acute hypoxaemic respiratory failure (AHRF) were enrolled within 72 h of onset of the syndrome. Eligible patients were required to be receiving invasive mechanical ventilation, non-invasive ventilation, or high-flow nasal oxygen. Plasma interleukin (IL-6) and soluble TNF receptor-1 (TNFR1) were quantified at enrolment using a near-patient benchtop immunoanalyser (Randox multiSTAT) with a run time of approximately 1 h. Together with plasma bicarbonate measured from an arterial blood sample, these values were used to prospectively determine subphenotypes on an individual patient basis using a validated parsimonious logistic regression model. The primary outcome was 60-day mortality. The study was registered on ClinicalTrials.gov, NCT04009330. FINDINGS:Between Nov 22, 2019, and Sept 28, 2023, 1853 patients from 30 centres were screened for eligibility. Of these, 1328 were excluded and 525 were recruited into the study, with 512 individuals included. 308 (60%) patients were male, 204 (40%) were female, and mean age was 57·0 years (SD 15·1). 443 (87%) patients were white, 18 (4%) were Black, and 16 (3%) were Asian. 490 were subphenotyped using the near-patient assay: 89 (18%) were classified as hyperinflammatory and 401 (82%) as hypoinflammatory. The primary outcome of 60-day mortality was measured in 486 patients after four patients withdrew consent for confirmation of vital status. 60-day mortality was significantly higher in the hyperinflammatory group (45 [51%] of 88) than in the hypoinflammatory group (111 [28%] of 398; risk ratio 1·8 [95% CI 1·4-2·4], p<0·0001). After adjustment, hyperinflammatory patients had increased odds of 60-day mortality (adjusted odds ratio 2·7 [95% CI 1·6-4·4], p=0·0002). INTERPRETATION:Rapid identification of ARDS inflammatory subphenotypes using a near-patient assay was feasible and associated with many clinical characteristics and outcomes consistent with those described in earlier retrospective studies, including mortality, prevalence of sepsis, and incidence of metabolic acidosis. These findings support the implementation of precision medicine approaches in ARDS and the urgent need for prospective, subphenotype-stratified interventional trials. FUNDING:Innovate UK, Randox Laboratories, and Belfast Health & Social Care Trust.

Sepsis-induced immunosuppression is a phenomenon characterized by the development of several changes in immunophenotype which predispose to secondary infections and increased mortality risk. Immunomodulatory therapies have yet to reproducibly demonstrate benefit in large clinical trials. We propose that several changes consistent with an immunosuppressive phenotype in sepsis represent either adaptive changes or epiphenomenon, rather than direct drivers of outcome in infection and sepsis. We therefore conducted a prospective observational study of patients presenting with infections with a spectrum of illness severity, to evaluate canonical features of monocyte and lymphocyte immunosuppression using flow cytometry. Several features consistent with immunosuppression in sepsis are observed in mild infections and non-infectious acute conditions. These features may be better understood as markers along a continuum of illness severity rather than distinct features of critical illness. Monocyte HLA-DR and co-stimulatory molecules (CD80 and CD86), and an increase in soluble PD-L1, discriminate between critically ill patients, patients with mild infection, and patients with non-infectious illness. In contrast, CD4+ and CD8+ lymphocyte phenotype did not discriminate between patient groups. Immunotherapies targeting lymphocyte function may only be effective if simultaneously augmenting monocyte antigen presentation and co-stimulatory pathways. Combination immunotherapy in sepsis requires evaluation.

Therapeutic modulation of sepsis-induced immune dysfunction by targeting lymphocyte dysfunction with recombinant IL-7 (rIL-7) and anti-PD-1 (e.g. nivolumab) has shown promise in preclinical and early clinical studies. Prior to conducting large randomized controlled trials, an in-depth understanding of the changes induced by rIL-7 or nivolumab (and their differences) in patients with sepsis is imperative. We performed a prospective observational cohort study including patients admitted to the intensive care unit with sepsis and characterized their T lymphocyte phenotype using flow cytometry. The ability of T lymphocytes to respond to a stimulus (using anti-CD3/CD28 beads) and the effect of rIL-7 or nivolumab on T lymphocyte immunophenotype ex vivo was assessed. In a cohort of 55 patients, CD4+ and CD8+ T lymphocyte PD-1 was higher and IL-7R lower compared with healthy volunteers. In a subset of 24 intensive care unit patients in whom in-depth immunophenotype was characterized, ex vivo response of lymphocytes to anti-CD3/CD28 beads was reduced compared with healthy volunteers, simultaneously inducing features consistent with immune activation and immunosuppression. rIL-7 was associated with a greater spectrum of changes compared with nivolumab. The response to rIL-7 and nivolumab was influenced by anti-CD3/CD28 bead costimulation. rIL-7 and nivolumab elicited distinct T lymphocyte responses ex vivo, and the changes were influenced by T lymphocyte activation. It needs to be determined if similar changes occur in vivo, which may influence the choice of immunomodulatory therapy in sepsis.

IntroductionReduced monocyte HLA-DR expression, a hallmark of immunosuppression in sepsis, is associated with infectious complications and mortality. Therapeutic strategies, including IFN-γ, have been used to restore monocyte HLA-DR and immune function, but have not consistently improved clinical outcomes. Therefore, we conducted an iterative series of experiments to re-examine the core assumptions and address the key gaps in the current understanding.MethodsWe conducted a prospective cohort study of patients admitted to the intensive care unit (ICU) with sepsis (n = 55, 36% mortality) to characterize the dynamics of monocyte HLA-DR expression and associated functional pathways. Flow cytometry was used to evaluate monocyte phenotype, and lipopolysaccharide (LPS) stimulation was used to assess monocyte functional capacity. We examined canonical monocyte pathways and identified those that were responsive to LPS stimulation and/or modulated by IFN-γ ex vivo. We evaluated monocyte HLA-DR expression in the peripheral blood and inflamed tissues of healthy volunteers following intradermal administration of UV-killed E. coli.ResultsMonocyte HLA-DR expression was significantly lower in patients than in healthy volunteers, particularly in non-survivors. Monocyte phenotypes evolved discordantly over time, some markers trended toward healthy levels, while others diverged, with no consistent distinction between survivors and non-survivors. Intracellular trafficking of membrane HLA-DR on bacterial phagocytosis contributes to the reduced surface HLA-DR expression. Compared to healthy volunteers, monocytes from ICU patients had a significantly lower expression of proteins associated with antigen presentation and co-stimulation, cytokines, phagocytosis, and a blunted response to LPS. IFN-γ increased the levels of proteins involved in antigen presentation, but their expression remained significantly lower than that in healthy controls. Healthy volunteers demonstrated compartment-specific and temporally distinct regulation of monocyte HLA-DR in circulation versus that in inflamed tissue.ConclusionReduced monocyte HLA-DR expression in sepsis reflects broad disruptions across multiple pathways, explaining the limited efficacy of therapeutic interventions. Further insights into the mechanisms governing therapeutic modulation of monocyte HLA-DR and immune function are required to identify patients who are most likely to benefit from intervention.

Adults who survive intensive care unit (ICU) admission with sepsis (sepsis survivors) have immune impairments involving concurrent inflammation and immunosuppression that increase their long-term risk of reinfections and mortality. Vaccine immunogenicity could therefore be abnormal in sepsis survivors but has never been examined. Here, in a 1:1 randomized, placebo-controlled trial, we tested the efficacy and immunogenicity of a single intramuscular dose of 13-valent pneumococcal conjugate vaccine (PCV13) in 214 sepsis survivors at ICU discharge. The PCV13 group (n = 104) experienced 43 primary outcome events (time to first infection-related rehospitalization or death during 365 days of follow-up) among 72.5 person-years of follow-up compared with 38 events among 76.5 person-years of follow-up in the placebo group (n = 110) [hazard ratio, 1.23 (95% CI, 0.80 to 1.91)]. The PCV13 group experienced higher rates of reinfections and received earlier antibiotic prescriptions in primary care. There were no vaccine-related serious adverse events. PCV13 immunogenicity assessments included serotype-specific immunoglobulin G (IgG), immunophenotyping, and pan-leukocyte RNA sequencing measured at baseline and 10 and 30 days postrandomization. PCV13-induced serotype-specific IgG responses varied across serotypes and participants, without excessive cytokine responses. PCV-induced blood transcriptional module responses in antigen-presenting cells and helper T cells were also variable. Variations in PCV13 immunogenicity were associated with age in men, body mass index in women, and cytotoxicity-associated gene modules regardless of sex. This trial showed that PCV13 administered at ICU discharge did not benefit this sepsis survivor population and underscores the need for further research to delineate treatable molecular mechanisms of postsepsis immune dysfunction (ClinicalTrials.gov identifier NCT03565159).

Sepsis causes muscle wasting and cachexia but mechanisms remain unclear. Cachexia in cancer and burn injury is partly attributed to 'browning'; where white adipose tissue (WAT) develops a catabolic, thermogenic brown adipose tissue-like phenotype. We hypothesised that sepsis-induced muscle wasting is caused by browning. 58 male Wistar rats were randomised to sham (n = 17) or experimental sepsis induced by intraperitoneal zymosan (n = 41). Tibialis anterior mass was measured on Days 3 and 14. Browning was sought using whole body and WAT respirometry, RNA-sequencing, immunoblot, thermal imaging and multi-photon microscopy of WAT. Fourteen-day mortality in rats receiving zymosan was 17%. In survivors, body mass loss peaked at day 3 and persisted to day 14 with associated tibialis anterior muscle mass loss. Zymosan peritonitis caused hypermetabolism during the late recovery phase (Days 11-14), but no difference in epididymal white adipose tissue temperature nor oxygen flux. At Day 14 transcriptomics showed inflammation but no increase in uncoupling protein (UCP)-1 at transcript or protein levels. SERCA2 protein was however increased fourfold in retroperitoneal WAT at day 14 (p = 0.016). Rats recovering from zymosan peritonitis developed muscle wasting and cachexia associated with WAT inflammation and whole-body hypermetabolism. No evidence of browning was seen at functional, transcriptomic or protein levels, therefore our data do not support the hypothesis of classical browning as a driver of sepsis-induced muscle wasting and cachexia. SERCA2 protein expression was however increased in retroperitoneal WAT at day 14.

Sepsis-induced cardiomyopathy (SIM) is characterized by myocardial dysfunction, diminished catecholamine responsiveness and worse outcomes. Hypocholesterolemia is also a well-recognized prognosticator of poor outcomes in sepsis. In vitro physiology/pharmacology studies indicate that low cholesterol levels within the cardiomyocyte membrane regulate ß-adrenergic receptor activity. We therefore hypothesized that cardiomyocyte membrane cholesterol levels are reduced in sepsis and this contributes to SIM. Cardiovascular biomarkers and plasma lipid profiles measured sequentially (6, 24 and 72 h) in a fluid-resuscitated rat model of fecal peritonitis were compared against those measured in 27 septic patients on Days 1–3 of ICU admission. In separate studies, rat hearts were excised at the same time points for measurement of cardiomyocyte membrane cholesterol and downstream adrenergic signaling. In a final study, the impact of a 15-hour infusion of cholesterol, either given as HDL-cholesterol or liposomal cholesterol, commencing at 6 h post-sepsis induction, on dobutamine responsiveness and cardiomyocyte membrane cholesterol levels was assessed. The magnitude of fall in stroke volume, rise in heart rate, plasma troponin and BNP, and fall in plasma HDL-cholesterol on ICU Day 1 in septic patients and at 6 h in the rat model all prognosticated for poor outcomes. In parallel, cardiomyocyte membrane cholesterol fell in the rats, more so in poor prognosis animals, with a blunted inotropic response to dobutamine, indicative of SIM. Cholesterol administration restored cardiomyocyte membrane cholesterol, dobutamine responsiveness and adrenergic signaling. In a long-term rat model of sepsis, that parallels changes seen in septic patients, cardiomyocyte membrane cholesterol fell with associated decreases in catecholamine responsiveness. These features could be restored by cholesterol infusion, suggesting potential utility as a therapeutic.

Importance Whether alpha(2)-adrenergic receptor agonist-based sedation, compared with propofol-based sedation, reduces time to extubation in patients receiving mechanical ventilation in the intensive care unit (ICU) is uncertain. Objective To evaluate whether dexmedetomidine- or clonidine-based sedation reduces duration of mechanical ventilation compared with propofol-based sedation (usual care). Design, Setting, and Participants Pragmatic, open-label randomized clinical trial conducted at 41 ICUs in the UK including adults who were within 48 hours of starting mechanical ventilation, were receiving propofol plus an opioid for sedation and analgesia, and were expected to require mechanical ventilation for 48 hours or longer. The median time from intubation to randomization was 21.0 (IQR, 13.2-31.3) hours. Recruitment occurred from December 2018 to October 2023; the last follow-up occurred on December 10, 2023. Interventions The bedside algorithms used targeted a Richmond Agitation-Sedation Scale score of -2 to 1 (unless clinicians requested deeper sedation). The algorithms supported uptitration in the dexmedetomidine- and clonidine-based sedation intervention groups and supported downtitration for propofol-based sedation followed by sedation primarily with the allocated sedation (dexmedetomidine or clonidine). If required, supplemental use of propofol was permitted. Main Outcomes and Measures The primary outcome was time from randomization to successful extubation. The secondary outcomes included mortality, sedation quality, rates of delirium, and cardiovascular adverse events. Results Among the 1404 patients in the analysis population (mean age, 59.2 [SD, 14.9] years; 901 [64%] were male; and the mean APACHE II score was 20.3 [SD, 8.2]), the subdistribution hazard ratio (HR) for time to successful extubation was 1.09 (95% CI, 0.96-1.25; P = .20) for dexmedetomidine (n = 457) vs propofol (n = 471) and was 1.05 (95% CI, 0.95-1.17; P = .34) for clonidine (n = 476) vs propofol (n = 471). The median time from randomization to successful extubation was 136 (95% CI, 117-150) hours for dexmedetomidine, 146 (95% CI, 124-168) hours for clonidine, and 162 (95% CI, 136-170) hours for propofol. In the predefined subgroup analyses, there were no interactions with age, sepsis status, median Sequential Organ Failure Assessment score, or median delirium risk score. Among the secondary outcomes, agitation occurred at a higher rate with dexmedetomidine vs propofol (risk ratio [RR], 1.54 [95% CI, 1.21-1.97]) and with clonidine vs propofol (RR, 1.55 [95% CI, 1.22-1.97]). Compared with propofol, the rates of severe bradycardia (heart rate <50/min) were higher with dexmedetomidine (RR, 1.62 [95% CI, 1.36-1.93]) and clonidine (RR, 1.58 [95% CI, 1.33-1.88]). Compared with propofol, mortality was similar over 180 days for dexmedetomidine (HR, 0.98 [95% CI, 0.77-1.24]) and clonidine (HR, 1.04 [95% CI, 0.82-1.31]). Conclusions and Relevance In critically ill patients, neither dexmedetomidine nor clonidine was superior to propofol in reducing time to successful extubation.

INHALE investigated the impact of seeking pathogens by PCR on antibiotic stewardship and clinical outcomes in hospital-acquired and ventilator-associated pneumonia (HAP and VAP). This pragmatic multicentre, open-label RCT enrolled adults and children with suspected HAP and VAP at 14 ICUs. Patients were randomly allocated to standard of care, or rapid in-ICU syndromic PCR coupled with optional prescribing guidance. Co-primary outcomes were superiority in antibiotic stewardship at 24 h and non-inferiority in clinical cure of pneumonia 14 days post-randomisation. Secondary outcomes included mortality, ICU length of stay and evolution of clinical scores. 554 eligible patients were recruited from 5th July 2019 to 18th August 2021, with a COVID-enforced pause from 16th March 2020 and 9th July 2020. Data were analysed for 453 adults and 92 children (68.4

Sepsis gene-expression sub-phenotypes with prognostic and theranostic potential have been discovered. These have been identified retrospectively and have not been translated to methods that could be deployed at the bedside. We aimed to identify subgroups of septic patients at high-risk of poor outcome, using a rapid, multiplex RNA-based test. Adults with sepsis, in the intensive care unit (ICU) were recruited from 17 sites in the United Kingdom, Sweden and France. Blood was collected at days 2–5 (S1), 6–8 (S2) and 13–15 (S3) after ICU admission and analyzed centrally. Patients were assigned into ‘high’ and ‘low’ risk groups using two models previously developed for the Immune-Profiling Panel prototype on the bioMérieux FilmArray® system. 357 patients were recruited (March 2021–November 2022). 69

Background: Hypertension therapy in older adults is often suboptimal, in part because of inadequate suppression of the renin-angiotensin-aldosterone system (RAAS). We hypothesised that distinct endotypes of RAAS activation before noncardiac surgery are associated with increased risk of myocardial injury. Methods: This was a prespecified exploratory analysis of a multicentre randomised controlled trial (ISRCTN17251494) which randomised patients >= 60 yr old undergoing elective noncardiac surgery to either continue or stop RAAS inhibitors (determined by pharmacokinetic profiles). Unsupervised hierarchical cluster analysis identified distinct groups of patients with similar RAAS activation from samples obtained before induction of anaesthesia, quantified by enzyme-linked immunoassays for plasma renin, aldosterone, angiotensin-converting enzyme 2, and dipeptidyl peptidase-3. The primary outcome, masked to investigators and participants, was myocardial injury (plasma high-sensitivity troponin-T). Results: We identified three clusters, with similar proportions of RAAS inhibitors randomised to stop or continue. Cluster 1 (n=52; mean age [standard deviation], 75 yr [8 yr]; 54% female) and cluster 3 (n=25; 75 yr [6 yr]; 44% female) had higher rates of myocardial injury (23/52 [44%] and 13/25 [52%], respectively), compared with cluster 2 with 51/164 (31.1%; n=153; 70 yr [6] yr; 46% female; odds ratio: 1.95, 95% confidence interval (CI) 1.12-3.39, P=0.018). Cluster 2 was characterised by lower N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentration (mean difference 698 pg ml-1, 95% CI 576-820 pg ml-1) and higher renin concentration (mean difference 350 pg ml-1, 95% CI 123-577 pg ml-1), compared with clusters 1 and 3 which had higher rates of myocardial injury. Conclusions: This mechanistic exploratory analysis suggests that effective preoperative RAAS inhibition is associated with lower risk of myocardial injury after noncardiac surgery, independent of stopping or continuing RAAS inhibitors before surgery. Clinical trial registration: ISRCTN17251494.

Hospital-acquired pneumonia (HAP) is a significant burden in nosocomial settings, yet its microbial underpinnings remain poorly understood. Here, we leverage shotgun nanopore sequencing to characterise the respiratory microbiomes of 250 HAP patients in a UK multi-site cohort, validating these using paired PCR and culture assays. Sequencing identified the dominant microbes implicated in HAP, including detection of probable pathogens in 49 PCR- and culture-negative cases. We found a high prevalence of fungi in 81/239 (34%) in HAP patients, of whom 26/81 (32%) were PCR/culture-negative, suggesting that fungi may represent an under-investigated component of HAP, whether as colonists or pathogens. Although HAP is clinically sub-categorised based on the use and duration of ventilation before disease onset, we found that the microbial profiles of these sub-groups were indistinguishable. We also found a concerningly high proportion of multi-drug-resistant microbes in HAP patients, with 21% of assembled bacterial genomes harbouring acquired antimicrobial resistance (AMR) genes that confer resistance to at least three classes of antimicrobials. This included high AMR gene carriage associated to Staphylococcus epidermidis , which may be an important reservoir of AMR, though typically viewed as a commensal. Our work provides extensive metagenomic characterisation of HAP, underscores the value of metagenomics in describing its complex aetiology, and further prompts its potential role for pathogen detection, resistance profiling and treatment.

Rapid molecular diagnostic tests improve antimicrobial stewardship (AMS) by facilitating earlier refinement of antimicrobial therapy. The INHALE trial tested the application of the BioFire FilmArray Pneumonia Panel (Pneumonia Panel) for antibiotic prescribing for hospital-acquired and ventilator-associated pneumonias (HAP/VAP) in UK intensive care units (ICUs). We report a behavioral study embedded within the INHALE trial examining clinicians' perceptions of using these tests. Semi-structured interviews were conducted with 20 ICU clinicians after using the Pneumonia Panel to manage suspected HAP/VAP. Thematic analysis identified factors reinforcing perceptions of the necessity to modify antibiotic prescribing in accordance with test results and doubts/concerns about doing so. While most acknowledged the importance of AMS, the test's impact on prescribing decisions was limited. Concerns about potential consequences of undertreatment to the patient and prescriber were often more salient than AMS, sometimes leading to "just-in-case" antibiotic prescriptions. Test results indicating a broad-spectrum antibiotic were unnecessary often failed to influence clinicians to avoid an initial prescription or de-escalate antibiotics early as they considered their use to be necessary to protect the patient and themselves, "erring on the side of caution." Some clinicians described cases where antibiotics would be prescribed for a sick patient regardless of test results because, in their opinion, it fits with the clinical picture-"treating the patient, not the result." Our findings illustrate a tension between prescribing guidelines and clinicians' "mindlines," characterized by previous experiences. This highlights the need for a "technology plus" approach, recognizing the challenges clinicians face when applying technological solutions to patient care.IMPORTANCERapid molecular diagnostic tests for pathogens and resistance genes may improve antibiotic-prescribing decisions and stewardship. However, clinicians' desire to protect their patients with antibiotics often overrides more distal concerns about possible resistance selection, limiting the application of these tests in practice. Findings underscore the challenge of changing prescribing decisions based on technical results or guidelines, highlighting factors such as clinicians' previous experience and "knowledge in practice" as more proximal drivers of these decisions. Implementation strategies for technological solutions to antimicrobial resistance must be "behaviorally intelligent," recognizing the challenges facing clinicians when making "life or death" prescribing decisions.CLINICAL TRIALSThis study is registered with ISRCTN as ISRCTN16483855.

Objective: The objective of this review is to identify immunological pathways and markers of severity of illness associated with clinical outcomes that may represent potential therapeutic targets in the management of secondary hemophagocytic lymphohistiocytosis. Introduction: A broad range of immunomodulatory therapies is used to manage hemophagocytic lymphohistiocytosis, however, the supporting evidence for these therapies is scarce. Identifying patients likely to experience more severe disease or die is currently extremely difficult, if not impossible. The identification of implicated cytokines in secondary disease can provide further support for the identification of high-risk patients and the development of targeted therapies. Inclusion criteria: Studies reporting immune biomarker and cytokine measurement in adult patients (age ≥18 years) with secondary hemophagocytic lymphohistiocytosis will be considered for inclusion. Methods: The proposed review will be conducted in line with the JBI methodology for scoping reviews. MEDLINE (Ovid) and Embase (Ovid) will be searched, without date limitations. Data will be extracted using a data extraction tool developed by the reviewers. Relevant sources will be retrieved, and their citation details imported into the JBI System for the Unified Management, Assessment and Review of Information. Review registration: Open Science Framework https://osf.io/9524e